I respond to some suggestions, mostly ones concerning things other than the game itself. For element suggestions, the reason I usually don't respond is because I'm not too interested in adding new elements. I wait for community feedback, and if it's positive, often one of our TPT Modders will code it and send a PR. Discussion of new elements mostly happens between us on IRC.

Most suggestions would just get a reply "this is rejected because I find it boring / too simple / too complicated", and I don't want to just comment that in every thread. I only reject and lock threads that break the element suggestion guidelines or have a clear reason to be rejected.